crowley



(No Model.) 4 sheets-sheet 1.

J. M. CROWLEY. TELBPHONEEXCHANGE SYSTEM.

No. 245,454. Patented Aug..9,18'81.

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(No Model.) 4 4 sheets-Sheen s. J. M. CROWLEY.

TELEPHONE EXCHANGE SYSTEM. No'. 245,454. Patented AugQQ, 1881.

ATTORNEYS.

(No Model.) 4 Sheets-Sheet 4. J. M. CROWLEY.

TELEPHONE EXCHANGE SYSTEM.

No. 245,454. Patented Aug. 9,1881.

l -wITNEsSgm- ATTORNYS.

PATENT JOHN M. CROWLEY, OF AUGUSTA, GEORGIA.

TELEPHONE-EXCHANGE SYSTEM.

SPECIFICATION forming part of Letters Patent No. 245,454, dated August9, 1881.

Application filed March 31, 1881. (No model.)

To all whom tt may concern:

Be it known that I, JOHN M. CROWLEY, of Augusta, in the county ofRichmond and State of Georgia, have invented a new and ImprovedTelephone-Exchange System; and I do hereby declare that the following isa full, clear, and exact description of the same, reference being had tothe accompanying drawings, forming part of this specification.

The object of my invention is, first, to enable all circuit wiresubscribers to avail themselves of the superior facilities of the Lawsystem as relates to the quick and always ready communication with thecentral-office operator, and at the same time lose none' of theadvantages cfa circuit-wire; secondly, to enable telephonie companiesowning the right to use the Law system to utilize the Law bells (with aslight alteration) for circuit as well as for single wires, therebyrelieving them of the absolute necessity of using electro-magnetocallbells, or similar special calling apparatus, on the one hand, orincurring, on the other hand, the expense of constructing independentprivate wires for each and every subscriber, or independent-call wiresfor certain circuit-stations. A further object is to secure uniformityof apparatus in general.

To these ends my invention contemplates the location of severalsubscribers on the same private wire runnin gin from the left and out atthe right and on to the terminal station, and thence tothe ground. Thegeneral central ottice call or tap wire is also connected, as usual,with the Lawsystem at these stations to communicate with the centraloftice, and a separate callbattery (which is only used for calling) islocated at each subscribers station, to call each other on the samecircuit with themselves.

My invention consists in the combination of these circuits with the Lawbell instrument, and in the application of a three-point back and frontcontact-key in connection with the call-battery at each station, and theprivate wire, which key and battery enable the subscriber at his homestation to call his neighbor or neighbors on the same private circuitwith facility at will and without the aid of the central-officeoperator; also permitting any individual subscriber on the circuit-wireto use the general tap-wire for communication to or representing theearth-connections.

from the central office, as is done by singlewire subscribers, all ashereinafter more fully described.

Figures l to 4 represent several stations, arranged in accordance withmy invention, in which Fig. l represents the'central office, Fig. 2 afirst station, Fig. 3 an intermediate station, and Fig. 4 a terminalstation, all on a privatecircuit wire. Each of the stations, Figs. 2, 3,and et are provided With a Blake transmitter, T, and a Law call-bell, L,arranged as hereinafter described. Fig. 5 is an enlarged verticalsection of the Law bell instrument; and Fig. 6 is an inside diagram viewof the same, showing the arrangement of the circuits therein.

In the drawings, Xis the general-call wire, which extends over all theprivate lines, and is tapped at t' into each one of the instruments otevery subscriber on all the private lines. This general call-wire isconnected with a listenin g operators telephone at the central ofiice,and also passes through the transmitter at said point, and thence to theground. The-tap-wire t' of the general-call circuit, after entering thebell of each subscriber, has aspecial or contingent outlet, j, to theearth, the `heavy ver-e tical margin-lines, which divide offthestations, Y is the private-line wire. This runs into each one of thesubscribers instruments at l and out at l2, passing through the normallyclosed contacts c c' ofthe back-and-forth contact-keys K, and aftertraversin g the instrument at the terminal station passes to the ground.This private wire Y at the central oliice connects with a spring-jack,E, which has a ground-connection that may be broken at will by anelastic coupling, G, connecting with a battery-plate, O, and battery A,by tapping upon which plate C by the end otl the connection G thecentral office may call any one on the private line.

Bis aspecial-call battery for each subscriber, which has oneearth-counectionand a wire, g, leading to a contact, f,- in front of thenormally closed contacts c, or on the opposite side of the three-pointkey K. This battery B has a normally broken circuit, and is only usedfor callin g,and when thus required the key K is pressed forward tocontact j', which makes a break at c in the 4private line, and closesthe battery B through the private line to one side or the IOO other ofthis subscriber, but not on both sides. Thus, at the iirst private-linestation, Fig. 2, the closing of key K on f calls all of the subscriberson the private line on the right. At this station but one key K isrequired, for the reason that this subscriber does not require a bell tocall central oliice, because the telephone atcentralofce, being onthelisteningoperators head, said subscriber can at once talk to centraloffice through his transmitter. At the second private-line station, Fig.3, (and other interme diate stations,) two keys, K K', are required.Byclosing key K on contact fthe call-battery B of that station is closedthrough wire g to the left, ringing the bells on the left to theground-connection oi' the central ofiice, but not on the right, becausebattery B of the second station is disconnected at f and makes a circuitonly through the half of the private-line circuit to the left. To callany ot' his neighbors on the right at this second or intermediatestation, key K is closed on contact j", which throws the battery B ofthat station onto the right-hand section'of the private wire, leavingconnection for the left-hand portion broken at j'. The result is thatthis will cause the bells ot' his neighbor or neighbors on the right toring, but will not disturb the bells of the neighbors 011 the left. Theterminal station, Fig. 4, is provided, like the first station, with onlyone key for calling' in one direction.

Each station is, as before stated, equipped with a Blake transmitter, T,and a Law hell, L. Each transmitter is provided with a talking-battery,T B, of a constant character, and the wire p c from which battery passesthrough the transmitter and constitutes the primary circuit. Thesecondary circuits c passes from the transmitter into the instrument Land then traverses the line.

I will now proceed to describe how theprimary circuit p c and thesecondary circuit s c are controlled within the Law bell-instrument.

Referring to Figs. 5 and G, which represent, in enlarged views, thestructure of the instrument L and arrangement of circuits within thesame, His a movable head or abutment, bearing two metal contacts, d d',which may be thrown into electrical connection with the twocorresponding contactplates 22 and 19 above or the two correspondingelectrical contacts 11 and 5, below. The two contacts 22 and 19 belongto the general call or tap wire, and connect respectively with the earthand the line, while the two contacts 11 and 5 belong t-o the privateline and connect with other wires within the instrument. The abutment Hhas a lever-handleJ H', projecting through a hole in the front ofthecase, which lever is normally held up with the contacts d d down uponplates 11 and 5 by the agency ot' springs N, but which lever may bepulled down at will to bring contacts d d upon plates 22 and 19, andthus throw the instrument oit' the private line and onto the generalcall or tap wire.

In the lower part of the instrument is a pivoted hook, b, and astationary hook, c, which are made to constitute two terminals of thecircuit-wire, so that when the telephone-ring is placed between thesections b and c the electric circuit is closed through 7 and 9, and themagnet of the telephone is eut out of circuit to avoid unnecessaryresistance to the line. When, however, the telephone is out and inoperative condition the circuit is shunted through wires 13 and 15, andmade to pass through the telephone to permit the message to be received.

In order to prevent the elements of the talking-battery TB from being'uselesslyconsumed when the telephone is hung up, the circuit of thistalking-battery is arranged to be broken by the act of hanging up thetelephone on its hook. This simultaneous breaking of the circuit of thetalking-battery and cutting out of the telephone-magnets by the act ofhanging up the telephone I do not claim as new. For this purpose,however, I introduce two plates, a a, within the instrument, whichconstitute the poles of the talking-battery, and when these poles areelectrically connected the talking-battery is operative, and when theyare disconnected the battery is inoperative. This connection anddisconnection I cause to be made by the end of the pivoted hook b, thuswhen the telephone is hung up the hook b is tilted and the poles a a aredisconnected, and when the telephone is out and operative the poles c aare connected by the tilting of hook b.

In order that the working ofthe instrument may be more clearlyunderstood, I will now proceed to describe the circuits for the different positions of the instruments.

We will suppose the instrument to occupy the position shown in Fig. 6,which is the normal position for communication between subscribers onthe private line. The current from the call-battery of the party wishingto communicate comes in at 1, passes up 2 to the bell, gives the call,and passes thence through 4, 5, d', 6, 7, 11,8, c, 9,19,d, 11, and 12,along the line to the ground, and thence to the call-bat tery whichgenerated it, the telephone of this instrument being out of the circuit,and this talking-battery inoperative. This subscriber then takes downhis telephone, which act establishes the circuit of his talking-batteryby closing the poles a, a and at the same time breaks the connectionbetween 7 and 9, which causes the current to be shunted through 13 tothe telephone, as shown in dotted lines, and thence to 15. Thissubscribers instrument is now in operative condition to hear and talkfrom the action of his talkin g-battery, and the call-battery of theother party is no longer required, and is inoperative. The primarycurrent then passes, as shown by the dotted lines, while the secondarycircuit s c traverses the lines to the ground, passing in theinstrumentfrom 1 to 2, to 3, through the bell-magnets, down 4 to 5, cl, 6, 13, 14,to telephone, 15 to 16, through transmitter 17, 18, 10, d, 11, 12,private line` to one ground-connection, and back to otherground-connection, to wire 1 again.

IOC

IIS

This is the action as between subscribers on the private line. 1f it isdesired to communicate with the cen tral office, the subscriber pullsdown his lever H, which act throws the metal plates d d out of contactwith 11 and 5, and in contact with 22 and 19. The result is that theWhole instrument is put upon the general call-line, and communicationwith the central office may be had in the same manner as just described.

The principal advantages of my invention are to be found, iirst, in thefact that subscribers ou a private line may call and communicate witheach other without the delay and embarrassment of calling the centralofce and waiting for the line to be free 5 and, secondly, in the greatreduction of the number of bell-ringings, which to many is a greatsource of annoyance. Furthermore, as the call-battery is lonly usedmomentarily for calling, no considerable consumption of battery materialis involved, which might otherwise be an obj ectiou to the use of somany batteries.

Having thus described my invention, what I claim as new is- 1. Thecombination of a general-call circuit, a special or private-linecircuit, a special-call battery for each subscriber, and one or moreback and front contact-keys, arranged in the private-line circuit andadapted to simultaneously break the private-line circuit and connectthel call-battery by the same movement, substantially as shown anddescribed.

2. The combination oi' a general-call circuit, a private-line circuit, aspecial-call battery for each subscriber, one or more back and frontcontact-keys, arranged in the private-line circuit and adapted tosimultaneously break the private-line circuit and connect thecall-battery, and an instrument, L, constructed substantially asdescribed, and having a set of contact-faces for the general-call line,a separate set of contact faces for the private line, and means forusing them interchangeably, as described.

JOHN CROWLEY.

